WESTPORT — Second-quarter testing from December has shown a noticeable reduction in the number of airborne PCBs at Westport Middle School, school officials said.

The testing results, which were revealed at Wednesday's School Committee meeting by Superintendent Carlos Colley, showed only two rooms with readings above the EPA's standard threshold of 300 nanograms per cubic meter.

This is down dramatically from the nine such rooms found in September's first-quarter round of testing, the results showed.

The two rooms that remain at unsafe levels both saw a slight reduction in PCB levels, but nothing substantial enough to get down to the EPA's level, Colley said.

A guidance office on the second floor went from 630 nanograms per cubic meter to 530 while Room 255 has gone from a 640 reading in September to 600 now.

The guidance office currently isn't in use. Room 255, formerly an office space, is now being used solely for storage.

Colley noted that the building is thoroughly cleaned in a two-week cycle and that the highest samples came from rooms that were the next scheduled for cleaning.

"During that two-week period you have dust collecting in the room" Colley said. "It's certainly possible that this could contribute to the high numbers."

Follow-up testing will be done.

Polychlorinated biphenyls which the EPA calls potential carcinogens were discovered in alarmingly high numbers at the middle school in the summer of 2011. Since then, substantial time and financial resources have been spent on removing them from the school. This process continued last week with the Board of Selectman's approval of a 19-year, $4.3 million loan to fund PCB removal and green repairs projects in the school district.

On another front, the School District received some good news with the arrival of a $25,000 grant from the Greater Fall River Development Corp. This grant will help fund the elementary school's purchase of the Journeys Reading Program, a curriculum overhaul intended to combat consistently low reading scores on the MCAS assessment test.